The A779 has a somewhat unusual hook shaped route, which would perhaps make more sense if it shared a number with the A7066, making the first section a short spur. This is not the case, however, so the route starts at the roundabout which provides access to the eastbound slip roads of Starlaw Interchange on the M8. From here it heads almost due west to the Boghall Roundabout, where it meets the A7066 and A89 and turns sharply left, crossing over the railway and then the motorway. The next roundabout serves the westbound slip roads to the M8, and is called Starlaw West Roundabout, despite being almost due south of Starlaw East Roundabout. These names presumably refer to the motorway carriageways they refer to. Now heading east along Starlaw Road, the route follows a wide alignment through tree lined fields which are predominantly reclaimed industrial land. Fields soon give way to the usual out-of-town offices and warehouses, including a large bonded site, to reach the edge of Livingston. The Tailend Roundabout gives access to northern parts of the town, while the A779 curves to the south east and soon ends on the A705 at the Toll Roundabout.
The route is built upon the general line, albeit much straightened, of the former B708, which was declassified at some point between 1948 and 1956. The route appears to have been thoroughly rebuilt and given the A779 number in the late 1980s when Starlaw Interchange was built. The old line of the B708 had already been changed by the construction of the motorway, and the addition of the Boghall Roundabout removed more evidence of the old road. Part of it survives, however, as Old Deans Road, serving a few properties. The cycle track through the trees to the north of Starlaw West Roundabout also shows the older road line, which then crossed Starlaw Road to serve the properties on the south side. Further on, the original line of Starlaw Road has again been repurposed as a cycle route, connecting to the A705 to the west of the Toll Roundabout.